Nozzle for gas turbines



May 9, 1933. M. SEDLMEIR NOZZLE FOR GAS TURBINES Filed Aug. 7, 1930 2Sheets-Sheet l bye/7 for fiflorne MW 1 1 a 5 5:: I 5 K2 1 \1. u I .w m F9 V Y I 7// 2 1 1 m.

2 Sheets-Sheet 2 Filed Aug. 7, 1930 Patented May 9, 1933 UNITED STATES.

mcnanr. ssnnmnra, or mutnmm on rnn-nnna, GERMANY, assxenony'ro nonz-PATENT OFFICE wan'rn .GAS roasmn so, clean rnancisco, caLironnrahoonronarion or y DELAWARE INOZZLE 203 Gas renames application meaaugun7, isaojsmarno. 473,142, and in Germany Airgun 23,1929.

My invention relates to nozzlesfor con ducting a fluid medium of suchhigh temperature as tonecessitate the employment of a cooling jacketabout such nozzles; and more particularlyto nozzles of the expansiontype forconducting to a turbine rotor the gases generated in theexplosion chamber of an explosion turbine. y

It is one of the objects of the present inventionto simplify themanufacture of a nozzle of the above-mentioned type and to provide anozzle of superior efliciency and reliability. It is also an objectofthe invention to provide a sectional nozzlewhose central por- 157 tionis formed of pressed metal so that machining thereof is renderedunnecessary while at the same time greater accuracy is secured. Otherobjects and advantages will appear from the following description andthe features of novelty will be pointed out in the claims.

In the acompanying drawings is shown by way of example a preferredembodiment of the invention. In said drawings, F i 1 is a longitudinalsection through the nozz e along the line I-I of Fig. 2; Fig. 2 is aview of the nozzle in elevation from the outlet end thereof; Figs. 3, 4and 5 represent transverse sections ta ken along the lines IIIIII,IV-IV,

and V-V, respectively, of Fi 1- Fig. 6 is a section along the line VI-Vof Fig. 1 and shows also the adjoining turbine parts; and Fig. 7 showsmy im roved nozzle 1n association with an explosion chamber and therotor of an explosion turbine.

My improved nozzle is of particular advantage in combustion gas turbinesand will be described in connection with such an apparatus.

a understood in the art, gases under high temrlture and pressure may begenerated within combustion chambers 1 (of which onl one is indicated inFig. 7 of the drawings) orming part of a gas turbine, such as anexplosion turbine of the constant volume type. In this latter tvne ofturbine, the explosion chambers are periodically charged with anexplosive mixture which is exploded therein,

b means not shown on the drawings, the nozzle valve 2 of each chamberbeing periodical- In such turbines, as is now well 1y opened to permitthe ases to discharge from the outlet end 3 oft e chamberinto a nozzlechannel 4. From the latter the gases flow into the gas nozzle by whichthey are directed against the rotor of a turbine, such rotorcomprising,forexample, two rows of blades 5, 6, between which arelocated stationary reversing bladesi'.

The gases entering the nozzle are of very high temperature, so thatthenozzlemust be providedwith a cooling jacket to prevent destructionthereof. With gas nozzles of the de Laval type, wherein the nozzle firstdimin+ ishes in cross-section from the inlet end thereof .to the throatsection, and then increases in cross-section from such throat toward theoutlet end, the latter being preferably curved to corres 0nd to. thecircle alongwhich the rotor bla es lie, the provision of such coolingjacket presents many. serious difii'culties.

When the nozzle body isformedas a sin 1e casting with as much aspossible of the j ac et cast integral with it, thedangerlexists,particularly with the larger and more compllcated castings, that all ofthe core is not removed, so that local overheating and burning out isliable to occur when the nozzle is in use. It is also very d-ifiicult tomachine the inner wallsof the nozzle castingalong which. the hot gasesflow so as to reduce friction losses. y l 1 i i In accordance with thepresentzinvention, I overcomemthese difficulties and gain certainimportant advantages by forming the nozzle inlet and outlet sections as.separate parts, while the central section, whose form determinesthevelocity and pressure rela tions of the gas fiowingtherethrou h, and istherefore the most critical part of t e nozzle,.I form of pressed metal,so that it possesses a smooth "interior. surface and thus reduces theenergy losses due to friction.-

of the nozzle, such as the cross-sectional area of the throat portion,can be attained thanin casting1 As s own in the drawings, the nozzlecomprises an inlet section 8, an outlet section 9, a

: are provided with jacket sections 16, 17

which extend in the direction of the nozzle axis and are connectedbywelding, as shown at: 33, 34, with a middlejacket or shell, so

that there is formed a cooling space 19 which,

extends for substantiallythe whole length of the as passageway 18.0f thenozzle.q.The :0 mid lecooling'jac et section, may, likethe middlesection of-the nozzle body, be formedofa U-shaped part 20 and acoverplate 23 welded to the and 5). $5 .The coolin enter the coo 'ngspace 19 at the outlet end of the nozzle through a conduct 24 (Fig. .6)

andiswithdrawn by conduit25 (Fig. l) atthe inlet end of the nozzle.

80 o The end sections 8 and 9 of the nozzle may be of cast steel, whilethe middle portion may be made of ametal or alloy welded with steel,such as mckel-copper-iron alloys or wrought iron plate. Because of 85the efiicient cooling of the nozzlebody by the aid of thecooling jacket,the inner walls of the nozzle need be only strong enough-to withstandthe pressure of the gases flowing through the nozzle, so that wroughtiron platelofi'ers a very satisfactory structural materia. I r

The inlet 26 of the nozzle is -of circular form, the inlet sectionrapidly diminishing in cross-section to the throat 27 which is inthe re'on ofjthe welding seam 10. From the throat27 the nozzle graduallyincreases in cross-section tothe. sector-shaped outlet 28. The shorteror upper nozzle wall is referably cut away in advance of theoutet,'as'shown'at 35, in orderto avoid the presence oftoo much metalbetween the cool ing space 19 and the inner surface of such wall. :The.end castings 8 and. 9 are provided with flanges 29 and30,-respectively, having openings 31 and 32to receive fastening meanswhereby the nozzle may befixed to the turbine frame. i Variations may beresorted to withinthe scope of the-appended claims withoutdearting.from-the spirit of the invention. or instance; the parts 12 and -20-neednot be made-of U-formbut may be given other shapes.

I claim: 7

1. A jacketed nozzle suitable for use with part 20 at 21, 22 (Figs. 3, 4

medium, such as water, may

adapted to beexplosion chambers, preferably in gas turbines, comprisingseparately cast inlet and outlet sections and a middle section formed ofsheet metal with a smooth surface and connected with the inlet andoutlet sections along lines transverse to the axis of the nozzle, theinlet section terminating'in the vicinity of the throat of the nozzle,the inlet and outlet sections having jackets integral therewith, and ajacket of sheet metal surrounding the middle section and connected withthe first mentioned jackets.

2. A nozzle suitable for use in explosion gas turbines, comprisinga bodyportion having separately formed'mlet, outlet and middle sections, saidvmiddle section-comprising a sheet-metal part of U-shape and a closureplate connected therewith, and a cooling jacket about said sections.

3. A nozzle suitable for use in explosion gas turbines, comprising abody portion having separately formed inlet, outlet'and middle sectionsand a cooling jacket about said sections, the portion of said jacketabout the middle section comprising a sheet-metal part of U-shape and aclosure plate connected therewith. I

7 MICHAEL SEDLMEIR.

